Although the meanings of the following acronyms are well understood by skilled artisans, the following list is deemed to assist in a better understanding of the invention:                3GPP Third Generation Partnership Project        AAA Authentication, Authorization, and Accounting        CCF Charging Control Function        CM Call Management        CS Cause        CSCF Call State Control Function        DA Destination Address        DCS Data Coding Scheme (3GPP TS 23.040)        DI Dialogue Identifier TCAP        EIR Equipment Identity Register        GGSN Gateway GPRS Support Node        GMSC Gateway MSC        GMSCA GMSC Address        GPRS General Packet Radio System        GSM Global System for Mobile Communication        HLR Home Location Register        IMS Internet Multimedia Subsystem        IMSI International Mobile Subscriber Identity        IWMSC Interworking MSC for SMS        MAL MSIsdn-Alert (3GPP TS 23.040)        MGCF Media Gateway Control Function        MGW Media Gateway        MMS More Messages to Send (3GPP TS 23.040)        MR Message Reference (3GPP TS 23.040)        MS Mobile Station        MSC/VLR Mobile Services Switching Center/Visitor Location Register        MSCA MSC Address        MSI Mobile Waiting Set Indication (3GPP TS 23.040)        MSIsdn Mobile Station ISDN number        MSM More Short Messages (3GPP TS 29.002[15])        MSRN Mobile Station Roaming Number        MT Mobile Terminal        MTI Message Type Indicator (3GPP TS 24.011[13])        MWD Messages Waiting Data        MWS Message Waiting Set (3GPP TS 23.040)        NAS Non Access Stratum        OA Originating Address        OC Operation Code (3GPP TS 29.002 [15])        OCS Online Charging System        PCF Policy Control Function        PCI Protocol Control Information        PDG/PDGW Packet Data Gateway        PDI Protocol Discriminator        PDN Packet Data Network        PDU Protocol Data Unit        PRI Priority (3GPP TS 23.040)        RAN Radio Access Network        RCT Reception Time (3GPP TS 23.040)        REA Recipient Address (3GPP TS 23.040)        RL Relay function (3GPP TS 24.011[13])        RP Reply Path (3GPP TS 23.040)        R-SGW Roaming SGW        SC Service Center        SC Service Centre (3GPP TS 23.040)        SCA Service Centre Address (3GPP TS 23.040)        SCTS Service Centre Time Stamp (3GPP TS 23.040)        SGSN Serving GPRS Support Node        SGW Signaling Gateway        SIP Session Initiation Protocol        SM Short Message (3GPP TS 23.040)        SM-AL Short Message Application Layer (3GPP TS 23.040)        SME Short Message Entity (3GPP TS 23.040)        SMI Short Message Identifier (3GPP TS 23.040)        SM-LL Short Message Link Layer        SM-RL Short Message Relay Layer (3GPP TS 23.040, 24.011[13])        SMS Short Messaging Service        SMS-GMSC Short Message Service Gateway MSC (3GPP TS 23.040)        SMS-IWMSC Short Message Service Interworking MSC (3GPP TS 23.040)        SoR Status of Report (3GPP TS 23.040)        SM-TL Short Message Transfer Layer (3GPP TS 23.040)        SRI Status Report Indication (3GPP TS 23.040)        SRR Status Report Request (3GPP TS 23.040)        TCAP Transaction Capabilities Application Part        TE Terminal Equipment        TID Transaction Identifier        T-SGW Transport SGW        TPDU Transfer Protocol Data Unit        UD User Data        UDL User Data Length (3GPP TS 23.040)        UE User Equipment        UMTS Universal Mobile Telecommunications System        UTRAN UMTS Terrestrial Radio Access Network        VP Validity Period (3GPP TS 23.040)        VPF Validity Period Format (3GPP TS 23.040)        WAG Wireless Access GatewayWLAN Wireless Local Area Network        
At the present time, the wireless industry is rapidly moving from voice to data services, from a verbal to a visual universe of applications. Users are demanding new features, such as the ability to send and receive emails, surf the World Wide Web (WWW), and send images, all from their wireless handheld terminals. The focus is on developing services, including advanced forms of messaging, mobile entertainment, and location-based applications that are available whenever and wherever they are needed.
One currently popular data service is known as “short message service”, hereinafter referred to as SMS. SMS has enjoyed ever-increasing popularity in many areas of the world, and this popularity is only expected to grow.
Short message services (SMS) are supported over existing wireless communication systems, including 2G GSM systems (i.e., circuit switch (CS) technology) and 2.5G GPRS systems (i.e., packet switch (PS) technology). The support of SMS is also provided over the most recent technologies (i.e., 3G UMTS and CDMA2000). However, the introduction of WLAN interworking with UMTS/CDMA2000 (or 3GPP/3GPP2 systems) has created a new environment that is not defined in terms of standard procedures and protocol architecture. Currently, there is no support for SMS over Interworked-WLAN systems. The overall architecture and procedures for UMTS/CDMA2000 based SMS are currently in the early development stage, and there are no standards or defined provisions for this purpose at this time. There is need for new protocol architecture for SMS over WLANs, in particular for a protocol for SMS services over WLAN interworked with UMTS/CDMA2000 systems.
The increased demand for mobile data communications raises some key interoperability challenges. Existing wireless networks have evolved during a time when voice, (not data), communications were of paramount importance. Early cellular network infrastructures included a radio access network coupled to a plurality of mobile switching centers (MSCs) which, in turn, were coupled to the Public Switched Telephone Network (PSTN). These devices operated in the circuit-switched domain, so as to implement voice communications. Unfortunately, the circuit-switched domain is highly inefficient when used to convey data communications, which led to the development of various alternate network topologies.
In GSM and GPRS architectures, the radio access network is coupled to one or more serving GPRS switching nodes (SGSNs) which, in turn, are coupled to one or more gateway GPRS switching nodes (GGSNs). The GGSNs are each coupled to an IP (Internet Protocol) network, which is either public or private. In this manner, the SGSNs and GGSNs implement packet-based switching to provide for efficient transfer of data between the radio access network and the IP network. Such data can include, for example, subscriber-originating short messages, subscriber-terminating short messages, IMS paging data, or other types of packet data.
If a mobile subscriber wishes to access the Internet (or a private Intranet) from a wireless handheld terminal, it is possible to do so via the radio access network, using a data communications pathway that includes one or more SGSNs, GGSNs, and an IP network. However, for many system applications, it would be desirable to access the IP network via another path, such as a wireless local area network (WLAN), to avoid adverse impacts on the ability of the radio access network to carry conventional voice communications.
WLAN technology is enjoying increased usage in homes, offices, and indoor public areas. Meanwhile, mobile service providers are exploring opportunities to extend their service portfolios by providing WLAN “hot-spot” access. By way of illustration, travelers waiting in airport lounges can access the Internet over a laptop computer that is equipped with a WLAN card. This enables end users to access their home office from virtually any location without any noticeable change in network performance. To support such services in commercial, enterprise and home networking environments, WLAN research and development is proceeding at a brisk pace. Rapid deployments of IEEE 802.11b, 802.11a and 802.11g are in progress, with a large number of companies involved in the design and manufacture of components based on the IEEE 802.11 Standards. These deployments are expected to increase as consumer interest increases.
Even though a WLAN provides a complementary service to GSM and other radio access network operators, interoperability standards have yet to be developed. As a result, subscribers do not have seamless coverage of all data services when switching between a radio access network and a WLAN. For example, in the context of a 3GPP-equipped network, subscribers are not able to receive SMS when they are accessing a WLAN. The ability to properly deliver other types of packet-switched or circuit-switched data, including IMS paging data, may also be compromised when a WLAN is utilized in conjunction with 3GPP equipment.
FIG. 1 sets forth a related art architecture for circuit and packet switching in the context of a GPRS and GSM network. An SM-SC 100 (short message service center) is coupled to an SMS-GMSC/SMS-IWMSC 102 (short message service-gateway message switching center/interworking message service center for SMS). SMS-GMSC/SMS-IWMSC 102 is equipped to operate using at least three different types of interfaces, set forth below.
A “C” interface operates between an HLR 104 (home location register) and SMS-GMSC/SMS-IWMSC 102. Each call originating outside of the GSM (such as an MS terminating a call sent from the PSTN) has to go through a gateway to obtain the routing information required to complete the call. A protocol known as MAP/C is used over the “C” interface for this purpose. Also, the MSC optionally forwards billing information to HLR 104 after call clearing.
A “Gd” interface, operating between SMS-GMSC/SMS-IWMSC 102 and SGSN 106, uses the MAP/G protocol to transfer subscriber information during a location update procedure.
An “E” interface operating between SMS-GMSC/SMS-IWMSC 102 and MSC/VLR 108 (mobile service switching center/visitor location register) interconnects two MSCs, and is used to exchange data related to handover between an anchor MSC and a relaying MSC using the MAP/E protocol.
A “D” interface is provided between MSC/VLR 108 and HLR 104. This interface uses the MAP/D protocol to exchange information related to the location of the MS and/or the management of the subscriber. A “Gs” interface is used between MSC/VLR 108 and SGSN 106. The “Gs” interface interconnects two VLRs of different MS Cs, using the MAP/G protocol to transfer subscriber information during a location update procedure. An “Iu” interface is employed between MSC/VLR 108 and a UTRAN 110 (UMTS terrestrial radio access network). Messages exchanged over the “Iu” interface are relayed transparently through a BSS (base station system). Finally, an “A” interface operates between MSC/VLR 108 and BSS 112. The “A” interface manages the allocation of suitable radio resources to the MSs, and also implements functions related to mobility and security management.
Terminal equipment, such as TE 114 and TE 116, may be coupled to mobile terminals, such as MT 118 and MT 120, respectively. Illustratively, communications between the TEs 114, 116 and the MTs 118, 120 takes place over an “R” interface. In turn, MT 118 communicates with UTRAN 110 over a “Uu” interface, and MT 120 communicates with BSS 112 over a “Um” interface. “Uu” refers to an over-the-air interface for exchanging information between a UMTS-equipped MT and a UMTS-equipped radio access network. Similarly, “Um” refers to an over-the-air interface between an MS and a BSS. The “Um” and “Uu” interfaces both use link access protocol-Dm channel (LAPDm), a modified version of the ISDN link access protocol-D channel (LAPD), for signaling.
UTRAN 110 is coupled to SGSN 106 using an “Iu” interface which, as previously mentioned, acts as a transparent relay for conveying messages between MSC/VLR 108 and an MS via BSS 112. A “Gb” interface is employed between BSS 112 and SGSN 106. The “Gb” interface is ultimately used to interconnect two VLRs of different MSCs, using the MAP/G protocol to transfer subscriber information during location update procedures, in this case via the BSS which has established communication with the MS. Subscriber information is also transferred during location update procedures using “Gs”, “Gr”, “Gn”, “Gi”, and “Gc” interfaces. The “Gs” interface links MSC/VLR 108 with SGSN 106; the “Gr” interface connects SGSN 106 with HLR 104; the “Gc” interface links HLR 104 with a GGSN 122; the “Gn” interface links SGSN 106 with GGSN 122; and the “Gi” interface links GGSN 122 with a PDN 124 (packet data network) coupled to TE 126.
SGSN 106 is coupled to an equipment identity register (EIR) 128 over a “Gf” interface. Basically, EIR 128 is a database which stores data related to mobile equipment. Whereas subscriber data is handled by HLR 104 and MSC/VLR 108, the EIR 128 stores relevant mobile equipment related data that may be employed, for example, to track down stolen mobile equipment, or to monitor malfunctioning mobile equipment. SGSN 106 is also coupled to charging gateway function (CGF) 130 over a “Ga” interface; and CGF 130, in turn, is coupled to a billing system 132. SGSN 106 may illustratively be coupled to an additional SGSNs, such as SGSN 134 through a “Gn” interface described previously. The SGSN is coupled to GGSN 122 by interface Gn and to GGSN 136 by interface GP. A CAMEL GSM-SCF (Customized Application for Mobile network Enhanced Logic, GSM Service Control Function) 138 is coupled to SGSN 106 by a “Ge” interface.
With respect to handling the Short Message Service (SMS), the overall requirements of the various elements of FIG. 1 (MSC/VLR 108, SMS-GMSC/SMS-IWMSC 102, and SGSN 106) provide message routing and intermediate buffering as set forth below.
(A) Requirements for Mobile-Terminating Short Messages
(i) Functionality of SMS-GMSC of SMS-GMSC/SMS-IWMSC 108
When receiving a short message TPDU (transfer protocol data unit) from the SM-SC 100, the SMS-GMSC of SMS-GMSC/SMS-IWMSC 102 receives the short message TPDU, and inspects the TPDU parameters. If the TPDU parameters are incorrect, the SMS-GMSC returns the appropriate error information to the SM-SC 100 in the form of a failure report. If errors are not found in the parameters, HLR 104 is interrogated and retrieves routing information or possible error information. In the case of error information, HLR 104 returns a failure report to the SC.
If no errors are indicated by HLR 104, then the short message TPDU is transferred to the MSC 108 or SGSN 106 using the routing information obtained from HLR 104. In cases where two addresses (SGSN and MSC) are received from the HLR 104, the SMS-GMSC may choose via which nodes (SGSN or MSC) the SMS is sent. SMS delivery via the SGSN is normally more radio resource efficient than SMS delivery via the MSC.
If one address (SGSN or MSC) is received from HLR 104, at the time the report associated with the short message is received from the MSC 108 or SGSN 106, the SMS/GMSC performs the following operational sequence:                (a) If the report indicates successful delivery/the HLR 104 is notified of successful delivery via the MSC 108 or the SGSN 106, which causes the HLR 104 to alert any service centers whose addresses are stored in the messages waiting data (MWD) for the MS; and the successful report is created and sent to the SC 100.        (b) If the report is a failure report indicating “absent subscriber” via the MSC 108 or the SGSN 106, then the HLR 104 is requested to insert the address of the originating SC into the MWD (if implemented) with the indication of absent subscriber; the HLR 104 is informed of the reason for the MS being absent via the MSC 108 or the SGSN (if this information is available); where necessary, a link is established with the addressed SC; and the negative report is created and sent to the SC which includes the reason for the MS being absent so that the SC may adjust any retry algorithm appropriately.        (c) If the report is a failure, a message is sent indicating “MS memory capacity exceeded” via the MSC or the SGSN by requesting the HLR 104 to insert the address of the originating SC into the MWD (if implemented) with the message “MS Memory Capacity Exceeded” via the MSC or the SGSN; establishing, where necessary, a link with the addressed SC; and creating and sending the report to the SC.        (d) If two addresses (SGSN and MSC) are received from the HLR 104, then upon receiving the first report associated with the short message from the MSC or SGSN, the SMS/GMSC 102 performs the following operational sequence. If the first report indicates successful delivery, the HLR 104 is notified of the successful delivery via the MSC or the SGSN, which causes the HLR to alert any service centers whose addresses are stored in the MWD for the MS; and the successful report is created and sent to the SC.        (e) If the first report is a failure report indicating any of a/an: unidentified subscriber, unsupported facility, absent subscriber with indication GPRS or IMSI Detach, system failure, unexpected data value, data missing, or GPRS connection suspended; then the short message TPDU is transferred to the second path using the routing information obtained from HLR 104.        (f) If the second report indicates successful delivery the HLR 104 is notified of the successful delivery of the second transfer via the MSC or SGSN, which causes the HLR 104 to alert any service centers whose addresses are stored in the MWD for the MS; the HLR 104 is notified of the unsuccessful delivery at first transfer only with cause “absent subscriber”; the HLR 104 is notified of the reason for the MS being absent via the MSC or the SGSN (if this information is available); when necessary, a link is established with the addressed SC; and the successful report is created and sent to the SC.        (g) If the second report is a failure report the HLR 104 requests to insert the address of the originating SC into the MWD (if implemented) only if at least one of the first or second report failed due to “MS Memory Capacity Exceeded” or “Absent Subscriber”; the HLR 104 is notified only with the causes “Absent Subscriber”, “Memory Capacity Exceeded” via the MSC or the SGSN, or both; the HLR 104 is notified of the reason for the MS being absent via the MSC, SGSN or both (if this information is available); where necessary, a link is established with the addressed SC; and the negative report is created and sent to the SC with errors from the first and second path.        
(ii) Functionality of MSC of MSC/VLR 108
When receiving a short message TPDU from SMS-GMSC/SMS-IWMSC 102, (“Forward Short Message”), the MSC performs the following operations: 1) receive the short message TPDU; and 2) retrieve information from the VLR (location area address and, when appropriate, error information).
If errors are indicated by the VLR; the MSC returns the appropriate error information to the SMS-GMSC in a failure report. If no errors are indicated by the VLR, the MSC transfers the short message to the MS.
When receiving a confirmation that the message is received by the MS, the MSC relays the delivery confirmation to the SMS-GMSC in a delivery report. When receiving a failure report of the short message transfer to the MS, the MSC returns the appropriate error information to the SMS-GMSC in a failure report. When receiving a notification from the MS that it has memory available to receive one or more short messages, the MSC relays the notification to the VLR.
If errors are indicated by the VLR, returning the appropriate error information to the MS in a failure report.
When there is an ongoing MT-SMS transfer to the MS, or other busy condition for the MT-SMS, the MSC has the option to store the TPDU in a queue for a short time (which must be shorter than the supervision timer defined in 3GPP TS 29.002 [15]). The maximum time that a message may be queued is related to the permitted delay for the MSC to respond to the SMS-GMSC. When the MS becomes available for MT-SMS transfer, the stored TPDUs are delivered to the MS on a first-in first-out basis. If a message is not successfully transferred to the MS within the permitted time, the MSC returns an appropriate error to the SMS-GMSC.
(iii) Functionality of SGSN 106
When receiving a short message TPDU from SMS-GMSC/SMS-IWMSC 102 (“Forward Short Message”), SGSN 106: receives the short message TPDU and, if errors are detected, the SGSN 106 returns the appropriate error information to the SMS-GMSC in a failure report.
If no errors are detected by the SGSN 106, the SGSN 106 transfers the short message to the MS.
When receiving a confirmation that the message is received by the MS, the SGSN 106 relays the delivery confirmation to the SMS-GMSC in a delivery report. When receiving a failure report of the short message transfer to the MS, the SGSN 106 returns the appropriate error information to the SMS-GMSC in a failure report. When receiving a notification from the MS that it has memory available to receive one or more short messages, if errors are detected by the SGSN 106, it returns the appropriate error information to the MS in a failure report. If no errors are detected by SGSN 106 it notifies the HLR 104 of memory available in the MS via the SGSN.
When the MS becomes reachable again it notifies the HLR of MS being reachable via the SGSN.
When there is an ongoing MT-SMS transfer to the MS, or other busy condition for MT-SMS, the SGSN has the option to store the TPDU in a queue for a short time (which must be shorter than the supervision timer defined in 3GPP TS 29.002 [15]). The maximum time that a message may be queued is related to the permitted delay for the SGSN to respond to the SMS-GMSC. When the MS becomes available for MT-SMS transfer, the stored TPDUs are delivered to the MS on a first-in first-out basis. If a message is not successfully transferred to the MS within the permitted time, the SGSN returns an appropriate error to the SMS-GMSC.
(B) Requirements for Mobile-Originating Short Messages
(i) Functionality of MSC of MSC/VLR 108
When receiving a short message TPDU from the MS, the MSC receives the short message TPDU; retrieves information from the VLR, as well as the MSISDN of the MS and, when appropriate, error information. The retrieval of information from the VLR is followed by the VLR investigating the mobile station not reachable flag (MNRF) to be used in the alerting procedure. If errors are indicated by the VLR, the MSC returns the appropriate error information to the MS in a failure report. If no errors are indicated by the VLR, the MSC inspects the RP-DA parameter.
If parameters are incorrect, the MSC returns the appropriate error information to the MS in a failure report. If no parameter errors are found, the MSC transfers the short message TPDU to the SMS-IWMSC of SMS-GMSC/SMS-IWMSC 102. Note that the functionality of the SMS-IWMSC may be implemented by the MSC.
When receiving the report of the short message from the SMS/IWMSC, the MSC is responsible for relaying the report to the MS.
(ii) Functionality of SMS-IWMSC of SMS-GMSC/SMS-IWMSC 102
When receiving a short message TPDU from the MSC or SGSN, the SMS-IWMSC receives the short message TPDU; establishes where necessary, a link with the addressed SC; and transfers the short message TPDU to the SC if the address is valid.
If a report associated with the short message is not received from the SC before a timer expires, or if the SC address is invalid, the SMS-IWMSC relays the report to the MSC or SGSN. If a report is associated with the short message is not received from the SC before a timer expires, or if the SC address is invalid, the SMS-IWMSC returns the appropriate error information to the MSC or SGSN in a failure report. The value of the timer is dependent on the protocol between the SC and the SMS-IWMSC.
(iii) Functionality of SGSN 106
When receiving a short message TPDU from the MS, SGSN 106 receives the short message TPDU and inspects the RP-DA parameter. If parameters are incorrect the SGSN transfers the short message TPDU to the SMS-IWMSC. When receiving the report of the short message from the SMS-IWMSC, the SGSN 106 relays the report the MS.
(C) SMS-IWMSC Functionality Related To Alerting
When receiving an alert from the HLR, the SMS-IWMSC of SMS-GMSC/SMS-IWMSC 102 inspects the switching center (SC) address; generates an RP-Alert-SC; and transfers the RP-Alert-SC to the SC. If the SC address is not valid, then no further action is taken.
(D) Fundamental Procedures Within SMS
SMS encompasses three fundamental procedures:                1) Short message mobile terminated (SM-MT). This procedure includes transferring a short message or status report from the SC to the MS; and returning a report to the SC, containing the result of the message transfer attempt.        2) Short message mobile originated (SM-MO). This procedure includes transferring a short message from the MS to the SC; and returning a report to the MS, containing the result of the message transfer attempt.        3) Transfer of an Alert. This procedure includes the operational sequences necessary for an HLR or a VLR to initiate a transfer of an Alert to a specific SC, informing the SC that the MS has recovered operation.        
Standard 3GPP TS 29.002 [15] defines operations required for the provision of the Short Message Service (SMS). The operations defined in clause 10 set forth the requirements that the SMS imposes upon network functionality. Annex C indicates the flow of primitives and parameters during the short message transfer between the SC and the MS. Both the mobile terminated (MT) and the mobile originated (MO) cases are covered.
Refer now to FIG. 2, which is a data structure diagram setting forth an illustrative related art SMS delivery mechanism over a GPRS and GSM-equipped network. The entities involved in SMS delivery include Short Message—Service Center (SM-SC) 100, SMS-GMSC/SMS-IWMSC 102, HLR 204, MSC/SGSN 206, VLR 208, and MS 220. SM-SC 100, SMS-GMSC/SMS-IWMSC 102, and HLR 204 (FIG. 2) are identical to the corresponding entities shown in FIG. 1, whereas the SGSN portion of MSC/SGSN 206 (FIG. 2) is analogous to SGSN 106 of FIG. 1, HLR 204 (FIG. 2) is analogous to HLR 104 of FIG. 1, and VLR 208 (FIG. 2) is analogous to the VLR portion of MSC/VLR 108 (FIG. 1).
Although FIG. 2 shows SM-SC 100 connected to a single MSC/SGSN 206 and illustratively involves a single public land mobile network (PLMN), as a practical matter, SM-SC 100 may be connected to several PLMNs and also to several MSC/SGSN's. SM-SC 100 is addressed from mobile equipment, such as TE 114 or MT 118 (FIG. 1) by an E.164 number. This number uniquely identifies SM-SC 100 to a particular PLMN.
Pursuant to the data flow diagram of FIG. 2, the short message delivery process begins when an SMS message is conveyed from SM-SC 100 to SMS-GMSC/SMS-IWMSC 102 (S1). In response to receipt of the SMS, SMS-GMSC/SMS-IWMSC 102 requests retrieval of routing information from HLR 104 (S2), and optionally sends an acknowledgement or not acknowledged message (ACK/NAK) back to SM-SC 100 (S3). HLR 104 responds by sending an MSC/SGSN address to SMS-GMSC/SMS-IWMSC 102 (S4). In the case of an error, SMS-GMSC/SMS-IWMSC 102 sends an error message back to SM-SC 100 (S5).
Now that SMS-GMSC/SMS-IWMSC 102 knows the address of the appropriate MSC/SGSN 206 as identified by HLR 104, the SMS-GMSC/SMS-IWMSC 102 sends the SMS to that MSC/SGSN 206 (S6). MSC/SGSN 206 attempts to locate the appropriate destination MS 220 for the SMS with help from VLR 208 (S7), and then forwards the SMS message to that MS 220 (S8). MS 220 then sends an acknowledgment or not acknowledged message (ACK/NAK) back to MSC/SGSN 206 (S9). MSC/SGSN 206 sends the ACK/NAK message to SMS-GMSC/SMS-IWMSC 102 (S10) which, in turn, relays the ACK/NAK message back to SM-SC 100 (S11). In the case of an error, an error message is sent from MSC/SGSN 206 to SMS-GMSC/SMS-IWMSC 102 (S12), and thence, from SMS-GMSC/SMS-IWMSC 102 to SM-SC 100 (S13).
FIG. 3 is a data structure diagram setting forth an illustrative prior art CS (GSM) paging procedure over a GPRS and GSM-equipped network using the A/Gb protocol. The entities involved in A/Gb-mode CS paging include MS 320, base station system (BSS) 112, SGSN 106, and MSC/VLR 108. BSS 112, SGSN 106, and MSC/VLR 108 (FIG. 3) are identical to the corresponding entities shown in FIG. 1, whereas MS 320 (FIG. 3) may correspond to TE 116 and MT 120 of FIG. 1. The paging procedure commences when MSC/VLR 108 sends a page to SGSN 106 (S1). The page may include some or all of the following parameters sent by the MSC: IMSI, VLR TMSI, Channel Needed, Priority, and/or Location Information. Channel Needed indicates to the MS the type of CS channel that must be requested in the response. VLR TMSI and Channel Needed are optional parameters. Priority is the circuit-switched paging priority parameter.
SGSN 106 responds to the page by sending a paging request to BSS 112 (S2). The paging request is a BSS-GPRS protocol (BSSGP) request to the BSS serving the MS that includes some or all of the following parameters: IMSI, temporary logical link identifier (TLLI), VLR temporary mobile subscriber identity (TMSI), Area, Channel Needed, and/or quality of service (QoS). The Area parameter is derived from either the MS's MM context in SGSN 106 or, if no such information is available, from the Location Information received from MSC/VLR 108. Area indicates a single cell for a READY state MS, or a routing area for a STANDBY state MS. VLR TMSI and Channel Needed are included if received from the MSC. If Channel Needed was not received from the MSC, then a default Channel Needed parameter indicating circuit-based paging is included by SGSN 106. QoS indicates the priority of this Paging Request relative to other Paging Request messages buffered in BSS 112. If the location area where the MS was last known to be located has an associated null routing area, then the SGSN 106 sends an additional BSSGP Paging Request message to each BSS serving the null routing area.
BSS 112 translates the incoming BSSGP Paging Request message into one Radio Paging Request message per cell. If a dedicated radio resource is assigned to the MS in a cell, then BSS 112 transmits one Paging Request (VLR TMSI or IMSI, Channel Needed) message on this radio resource (S3), without stopping possible outgoing data transfers for the MS. Otherwise, BSS 112 pages the MS with one paging request (VLR TMSI or IMSI, Channel Needed) message on the appropriate paging channel in each addressed cell.
Responsive to BSS 112 forwarding the paging request to MS 320, MS 320 sends a set asynchronous balanced mode (SABM) message to BSS 112 (S4). BSS 112 responds to the SABM message by sending a signaling connection control part (SCOP) connection request to MSC/VLR 108 (S5). In cases where MS 320 is both IMSI and GPRS-attached in a PLMN that operates in mode I, the MSC/VLR executes paging for circuit-switched services via SGSN 106. Upon receipt of a Paging Request message for a circuit switched service, MS 320 may elect to respond to this request and, pursuant to such an election, the MS will follow standard, well-known CS procedures for paging response (random access, immediate assignment) as specified in GSM 04.08[13]. When received at BSS 112, the Paging Response message is sent to the MSC, which then stops the paging response timer.
Refer now to FIG. 4, a data structure diagram of a prior art CS (GSM) paging procedure over a GPRS and GSM-equipped network using the “Iu” protocol is shown. The entities involved in Iu-mode CS paging include MS 420, RNS 412, 3G-SGSN 406, and MSC/VLR 408. The paging procedure commences when MSC/VLR 408 sends a page to 3G-SGSN 406 (S1). The page may include some or all of the following parameters sent by the MSC/VLR: IMSI, VLR TMSI, Channel Needed, Priority, and/or Location Information. If VLR TMSI is not included, the IMSI is used instead of the TMSI as a paging address at the radio interface. If Location Information is not included, 3G-SGSN 406 pages MS 420 in all cells served by MSC/VLR 408 and 3G-SGSN 406, unless 3G-SGSN has reliable information about the location of MS 420.
3G-SGSN 406 responds to the page by sending a radio access network application part (RANAP) paging message to each radio network subsystem (RNS) 412 (S2). The RANAP paging message includes some or all of the following parameters: IMSI, TMSI, Area, and core network (CN) Domain Indicator. RNS 412 requires the IMSI parameter in order to calculate the MS 420 paging group, and to identify the paged MS 420. The TMSI parameter is included if it is received from MSC/VLR 408. The Area parameter indicates the area in which MS 420 is paged, and it is derived either from the MS's MM context in 3G-SGSN 406 or, if no such information is available, from the Location Information received from MSC/VLR 408. CN Domain Indicator indicates which domain (CS or PS) initiated the paging message and, in the present scenario, it must be set to “CS” by 3G-SGSN 406.
Upon receipt of a Paging Request message for a circuit-switched (CS) service (S3), MS 420 responds to this request and returns a paging response (S4) in the form of a radio resource control (RRC) Initial Direct Transfer message (refer to GSM 04.18 and 3GPP 25.331 for more details). The CN Domain Indicator is set to “CS” in the Initial Direct Transfer message. When received at RNS 412, the Paging Response message is sent in an RANAP Initial UE message to MSC/VLR 408 (S5), which then stops the paging response timer.
FIGS. 5 and 6 are data structure diagrams setting forth illustrative prior art GPRS network-initiated service request procedures. The entities involved in the procedures of FIGS. 5 and 6 include MS 520, SGSN 506, HLR 504, and GGSN 522. In addition, the procedure of FIG. 6 employs a radio network controller (RNC) 612.
Referring first to the procedure of FIG. 5, a packet data protocol, protocol data unit (PDP PDU) is received at GGSN 522 (S1). GGSN 522 sends routing information for GPRS to HLR 504 (S2). HLR 504 sends an acknowledgment message back to GGSN 522. GGSN 522 then sends a PDU notification request to SGSN 506 (S3). SGSN 506 responds to the PDU notification request by sending a PDU notification response back to GGSN 522 (53A). SGSN 506 then requests packet data protocol (PDP) context activation from MS 520 (S4). MS 520 and GGSN 522 then engage in a PDP context activation procedure (S5).
With respect to the procedure of FIG. 6, when SGSN 506 (in this case, a 3G-SGSN) receives a downlink packet (Request PDP Context Activation, MT SMS, User Data) for an MS in packet mobility management-IDLE (PMM-IDLE) state (S1), SGSN 506 sends a paging request (S2A) to the MS520 using RNC 612 (S2). The paging request triggers the service request procedure in MS 520 (S3). The overall service request procedure operates as follows. First, SGSN 506 receives a downlink PDP PDU for MS 520 when the MS is in PMM-IDLE state. Next, SGSN 506 sends a paging message to RNC 612. RNC 612 pages MS 520 by sending a paging message to the MS. MS 520 establishes an RRC connection into the RNC 612 if none exists for CS traffic (S3, S3A).
The service request procedure continues when MS 520 sends a Service Request message (S4) to SGSN 506. A Service Request message includes one or more of the following parameters: P-TMSI, routing area identification (RAI), cipher key sequence number (CKSN), and Service Type. The Service Type parameter specifies the paging response (PR). The Service Request is carried over a radio link in an RRC Direct Transfer message and over the Iu interface in the RANAP Initial MS message. At this point, SGSN 506 may perform an authentication procedure. SGSN 506 is able to ascertain whether the downlink packet requires radio access bearer (RAB) establishment (i.e., downlink PDU) or does not (i.e., Request PDP Context Activation or MT SMS). SGSN 506 then performs the security mode procedure (S5).
If resources for the PDP contexts are reestablished, SGSN 506 sends an RAB Assignment Request (S6A) to RNC 612. The RAB Assignment Request includes one or more of the following parameters: (RAB ID(s), tunnel endpoint identifiers (TEIDs), QoS Profile(s), and SGSN IP Address(es)). RNC 612 sends a Radio Bearer Setup message (S6B), including one or more RAB ID(s), to MS 520. MS 520 responds to the Radio Bearer Setup message by returning a Radio Bearer Setup Complete message to RNC 612 (S6C). RNC 612 sends an RAB Assignment Response message to SGSN 506 (S6D) in order to indicate that GPRS tunneling protocol (GTP) tunnels are established on the Iu interface, and also to indicate that radio access bearers are established between RNC 612 and MS 520. The RAB Assignment response includes one or more of the following parameters: (RAB ID(s), TEID(s), and RNC IP Address(es)).
If RNC 612 returns a RAB Assignment Response message with a cause indicating that the requested QoS profile(s) cannot be provided (for example, the maximum requested bit rate is not available), then SGSN 506 may send a new RAB Assignment Request message specifying a different QoS profile or profiles. The number of re-attempts, if any, as well as the manner in which the new QoS profile(s) are determined, are implementation dependent. For each RAB reestablished with a modified QoS profile, SGSN 506 reinitiates a PDP Context Modification procedure to inform MS 520 and GGSN 522 of the new negotiated QoS profile for the corresponding PDP context (S7). SGSN 506 then transmits the downlink packet (S8).
Although FIGS. 1-6, teach the ability to deliver SMS and IMS paging over a cellular network there is a lack of systems and methods for delivering data-based services, such as SMS and IMS paging, over a WLAN.